The present invention relates to the field of plant growth units.
Plant growth units which attempt to conserve horizontal space and utilize vertical space, are known. A typical hydroponic plant growth system comprises a nutrient base and circulates a liquid nutrient through a cultivation portion wherein the plant seeds or young plants are anchored. For example, U.S. Pat. No. 5,502,923 discloses a hydroponic plant growth system which consists of a nutrient supply module base which supplies liquid nutrient to a series of vertically stacked prop modules, each prop module containing a number of plant growth sites. As liquid nutrient is pumped to each prop module, water is distributed to the plants grown therein.
U.S. Pat. No. 4,986,027 discloses a plant growth apparatus comprising a flexible tubular element wherein slits are provided for the growth of plants. A fluid nutrient is supplied to the root permeable material via a pump system, the fluid nutrient thereby being supplied to the plants.
Similarly, U.S. Pat. Nos. 5,440,836, 5,555,676, 5,918,416 and 4,033,072 all disclose vertical growing columns for growing a number of plants which are supplied water and nutrients through the use of nutrient solution pumps in the base of the respective apparatuses, which supply liquid nutrient to the top of the apparatuses. The liquid nutrient is supplied to the plants as the liquid travels from the top of the apparatuses to the bases.
Further, the prior art indicates that multiple vertical plant grow columns may utilize a single nutrient base. For example, U.S. Pat. No. 5,363,594 discloses a structure for a vertically oriented plant growth unit having a plurality of vertical columns arranged to conserve horizontal floor space and utilize a common base for the supply of liquid nutrient.
One of the potential limitations of the growth units described above is that the various plants of the growth units may receive different types and amounts of light from whatever light source is utilized. The differences in light quality and quantity may result in a divergence in growth and quality between plants grown at various levels and on various sides of the vertical columns.
U.S. Pat. No. 6,178,692 discloses a lighting system for use with one or more vertical growing columns. The lighting system is mobile and can apparently be angled to provide for equidistant lighting to the plants at both the top and the bottom of the vertical growth column. However, it would appear that equidistant lighting is to be provided by the lighting apparatus to a single side of each growth column. Each vertical column apparently has plants growing on all sides of the vertical unit and therefore a single lighting unit would appear only to provide equidistant lighting to those plants which are somewhat facing the lighting unit. To provide equidistant lighting to all plants on the growing columns, it would appear that two lighting units are set up on either side of one or more growing columns and angled to provide top to bottom equidistant lighting on each side of the vertical grow columns, thereby providing equidistant lighting to all plants. In at least some embodiments, this system therefore appears to be limited by the requirement for multiple lighting units to create equidistant lighting to all plants.
In one aspect, the present invention provides a plant growth unit including a nutrient supply module, one or more columns and a plurality of growth sites supported by the one or more columns. The nutrient supply module may be designed to contain a liquid nutrient. The one or more columns may be radially disposed about a central vertical longitudinal axis to define an internal space between the one or more columns. The internal space may be adapted to acconmmodate a light source. Each column may have an upper portion, a lower portion and a longitudinal passage through which the liquid nutrient may pass. Further, each column may be in fluid communication with the nutrient supply module for circulation of a liquid nutrient flow from the nutrient supply module to the upper portion of each of the one or more the columns and through the longitudinal passage to the respective lower portion of each of the one or more columns. The plurality of growth sites may be radially disposed about the longitudinal axis of the growth unit, generally facing the internal space, and each growth site may be positioned to contact the liquid nutrient flow.
In some embodiments, there are at least two columns and at least one growth site on each column. Such columns may be vertically oriented. In yet other embodiments, the growth unit has at least three columns, which may be circumferentially disposed in a generally circular pattern. In other embodiments, there is only one column which contains a plurality of growth sites. In such an embodiment, the single column defines its internal space by, for example, coiling around the longitudinal axis.
In accordance with some embodiments, two or more of the growth sites are approximately equidistant from the longitudinal axis. In other embodiments, at least two growth sites are located on each of the one or more columns and at least some of the growth sites on each column are vertically spaced apart. In such an embodiment, the growth sites at generally the same vertical level may be approximately equidistant from the longitudinal axis. In still other embodiments, the growth unit comprises at least two columns and at least two growth sites are located on each column. In such an embodiment, the growth sites on each column may be vertically spaced apart, and growth sites at generally the same vertical level may be approximately equidistant from the longitudinal axis.
The nutrient supply module may act as a base into which the columns are located, and may be shaped to facilitate balance of the system, such as disc shaped. The columns may be shaped to facilitate the nutrient flow from the upper portion of each of the columns to the lower portion of each of the columns, such as tubular columns.
The plant growth unit may further include one or more fluid connectors, such as tubes, which connect the nutrient supply module with the upper portion of each of the one or more columns. The fluid connectors may be designed to facilitate the liquid nutrient flow from the nutrient supply module to the tops of each of the one or more columns. The plant growth unit may also include a pump, or pumps, facilitating the liquid nutrient flow.
Where each column supports a plurality of growth sites, the growth sites may be longitudinally aligned. In some embodiments, the growth sites may protrude upwardly from the columns. The plant growth unit may also include a plurality of baskets which are designed to hold plants and designed to attach to the growth sites. The plants may be anchored to the growth unit by being placed inside the baskets, which are then attached to the growth sites.
Other embodiments of the present invention provide methods for growing plants in a growth unit. A nutrient supply module may be adapted for holding a liquid nutrient. One or more columns may be radially disposed about a central vertical longitudinal axis of the growth unit, thereby defining an internal space between the one or more columns. The columns may be disposed in fluid communication with the nutrient supply module and the internal space may be adapted to accommodate a light source. Each column may be designed with an upper portion, a lower portion and a longitudinal passage through which the liquid nutrient may pass. The nutrient supply module may be connected to the upper portion of the columns. A plurality of growth sites may be provided supported by the columns. The growth sites may be disposed radially about the longitudinal axis and generally facing the internal space. A plurality of plants may be then be located in the growth sites and the liquid nutrient may be added to the supply module. The liquid nutrient may then be circulated from the nutrient supply module to the upper portion of each of the one or more columns, through the longitudinal passage to the respective lower portion of each of the one or more columns. During its circulation, the liquid nutrient may be brought into contact with the plants.
In such a method, the introduction of a plurality of growth sites may further include locating at least two of growth sites equidistant from the longitudinal axis. During the introduction of a plurality of growth sites, at least two growth sites may be introduced on each of the one or more columns, at least some of such growth sites being vertically spaced apart on the columns. In such a method, the growth sites being at generally the same vertical level may be located approximately equidistant from the longitudinal axis. In another such method, at least two columns may be disposed and at least two growth sites may be introduced on each of the columns, such growth sites being vertically spaced apart on each column. In such a method, the growth sites which are at generally the same vertical level may be located approximately equidistant from the longitudinal axis.
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only, and not as limiting the invention to particular embodiments.